A strain sensing device can be attached to a structural member, such as an implant device subject to mechanical loading, to monitor the strain applied to the structural member. For example, U.S. Pat. No. 9,326,728 (hereafter Reference 1) discloses a wireless strain sensor having a resonating circuitry that is mounted to a structural member, including an implant device, and US 2007/0186677 discloses monitoring the strain applied to a target structural member, using one or more wireless strain sensors attached to the surface(s) of the target structural member, by monitoring the signals transmitted and/or reflected from the strain sensor using a known RF signal source.
Although using one or more strain sensors in the manner disclosed in Reference 1 can be beneficial in that the reflected resonance frequency can be set by designing the wireless sensor that is attached to the structural member, the strain sensors need to be imprinted, otherwise fabricated, or attached to the structural member to monitor the strain, increasing the cost and complexity of the system. It would be desirable to simplify the manner of monitoring deformation applied to a structural member by eliminating the in-dwelling strain sensor, which is in contact with the structural member. The present invention addresses this need.